Paint remover composition



Patented May 16, 1950 UNITED STATES PATENT OFFICE Lester E. Kuentzel, Wyandotte, Mich., assignor to Wyandotte Chemicals Corporation, Wyandotte, Mich., a corporation of Michigan Application November 1, 1945, Serial No. 626,173

4 Claims. (01. 252-143) This invention relates to compositions for removin or stripping paint, varnish, enamel, lacquer and the like from surfaces of metal, wood, glass, fabrics or brushes. The prime objective of my invention is to provide a paint remover which has high stripping power, 1. e. capable of looseningthe coating in a minimum period of time. This property is highly desirable in a paint remover since it contributes both to the reduction of time and labor required for stripping, as well as to the efiiciency of the action of the remover.

Chlorinated aliphatic hydrocarbon solvents have heretofore been used and formulated to a considerable extent as ingredients of paint removers. I have made the discovery that the presence of a small amount of certain selected acids greatly improves the stripping power of methylene chloride; and that the addition of a small amount 01' water to the methylene chloride and acid mixture imparts still greater strip ping power.

Both acid and water ingredients of the paint remover embodying the principle of my invention are thus believed to function as solvent activating catalysts, which result in ,the remarkably enhanced stripping power oi the methylene chloride solvent.

Additional objectives and advantages of my in-- vention shall become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the following description and annexed drawing set forth in detail the nature of my invention and the best mode of applying the principle thereof whereby those skilled in the art may be enabled readily to understand and practice same.

The annexed drawing is a chart, on logarithmic scale, showing the relationship between the stripping power and variation in water and acid additives on methylene chloride.

The particular acids, whether organic or inorganic, which are capable of imparting the desired activating action to methylene chloride do upon the stripping ability being substantially as of the order given:

Formic Carbolic (phenol) Acetic Nitric Propionic Benzoic Salicylic Cinnamic Butyric It is recognized that chlorinated hydrocarbon solvents in general, and methylene chloride to a slight extent, have the tendency to decompose after a period of time or to hydrolyze in the presence of moisture, light, and elevated temperatures, to form hydrochloric acid. However, such a possible latent or inherent presence of acid in the methylene chloride solvent is obviously not included withinthe purview of my invention, since not only does my invention'contemplate the addition of an acid not inherently present or generated in the methylene chloride, but also, hydrochloric acid is one of those acids which have been found to depress rather than promote, the stripping power thereof.

Additional ingredients including thickeningagents, blending agents, an evaporation retard;

ant, (such as parafiin wax) and Wetting agents. (such as alkylated aromatic sodium sulfonates) may also be incorporated to advantage into the compositiom-as more fully set forth in my copending application Serial No. 626,172 filed November 1, I945. These wetting agents are of particular advantage'because they impart a greater removability of the paint remover composition by water, even when water-insoluble materials such as wax and methyl cellulose are present. Wetting agents of the alkyl aryl sulfonate type have been found to be quite satisfactory in the formulation of compositions embodying the principle of my invention. Specifically, alkyl aryl sulfonate wetting agents are available on the market under the trade names offSantomerse D and Wetsit Concentrated. Santomerse D is a substantially 99% dodecylbenzene sodium sulfonate. Wetsit Concentrated is a proprietary alkyl aryl sulfonatehcontainin a minor proportion of terpenes and about 20% water content. The alkyl. and aryl groups of such latter form of alkyl aryl sulfonate are not definitely known or publicized, such information being the private property of the manufacturer of such product. Wetslt Concentrated is particularly suitable since it contains approximately 20% water and thus serves as a convenient means for adding the water ingredient to the composition, making it unnecessary to add water separately as there is enough Water in such wetting agent to satisfy the formulation requirements.

The remarkable ability of relatively small amounts of water'and acid to enhance or accelerate the stripping power of the methylene chloride is shown in the following tabulated results where methylenechloride alone, andmethylene chloride containing -:water and different selected acids (separately and jointly) were applied to standard painted test panels. These test panels comprised U. S. Navy panels 72 and 75E as recited in Navy Aeronautical Specification:C-:1l3. Amendment-2; and United States Army Air Force test panels Nos. 14105. and 14109,"as'-recited in Army Air Force Specification No. 14119. The detailed description of these stripping'test panels is set forth in my copendin-g application Serial No. 509,121, now U. S. Pat. No. 2,433,517 issued Dec. 30, 1947.

' "Table I Stripping Power (time in g fgg t' B seconds to completely waterAdded loosen coating from panels) to Methylene ohlmde 14105 14109 0. 000 .over. 10, 000- 9000 0.003 'over' 10, 000 1500 0. 015 0,400 720 0.030 3,-300v 1600 0. 073 900 300 l l 0.15 .1480 .1150 :5. 500 .150

. fiaturated solution of water. in methylene chloride .The. methylene chloride used in the mixtures of .the foregoing'fla'ble II was first carefully distilledto remove "any possible .trace .of water.

.Curve. I .in .the drawing shows the relationship of, stripping power on panelfNo. 14105 .to percentage of waterpresent. ,It will be .seen that the .maximum .str ipping power .is reached at about 03% .Water ,content and it. ismaintained up through. .5.

,C.urve-2 in thedrawing illustratesthe manner in which the addition. of. acetic acid accelerates 4 improvement is quite rapid from 0.1 to 10% and thence it drops off a little more slowly.

Curves represents the 0.15% constant water- .acetic -acid-methylene chloride composition and :curve 4 is the 5.0% water-acetic acid-methylene chloride composition, wherein the change in strippingpower'on'panel No. 14105 as the acetic acid content is increased, is shown. It is to be noted that the presence of both water and acetic acid imparts a stillugreater stripping power than in .the case of acetic acid addition only. Comparecurves 3. and i-withcurve 2.

Table IV by 2235535002253.5111; g loosen coating from Acid Added Panels) to Methylene Chlmde 14105 14109 0. 000 over 10,000 9000 O. 5 3, 600 3000 1. 0 3, 000 2400 4. 76 540 240 7. 40 9. 09 75 150 11. 7 60 150 16. 6 2.45 150 20. 0 30 150 25. 0 30 150 28.0 30v 150 33;; 30 150 A10. 0 V 30 50. 0 30 225 55. 5 45 240 60. 6 I 60 300 76 9 60 .510 83.3 V 00 600 00' 9 75 780 99. 0 120 1200 100. 0 120 1500 In the .above table, the use of 88% phenol necessarily includes the presence of varying eamounts of water, i. e., 12% of the stated percentage of 88% phenol.

Curve 501 the drawing plots the values given in Table IV for panel No. 14105. It should be noted that the characteristics of this curve are very similar to thoseof curve 2 (acetic acid and methylene chloride), although higher percent- .ages .of 188% phenol are requiredto attain similar stripping time values. At above approximately 50% acid -content (anhydrous basis) for both curves 2 and 5, the stripping time begins to drop oifagain and becomes greater than one minute. This .efiect.is, of course, all the more sharply pronounced in the case of .the stripping .time valuesfor panel No.114109. For not only this reason, but also. forcommercial, economic and safety considerations.anacidcontent .of 50% by weight of the total composition becomes the maximum .thestrippingpower of methylene chloride. The .upper limit.

I Table V j 1 1., V

Composition 0! Re- 7 d Q pping Power- (time in seconds to completely .flf igg f f loosen coating from panels) L w Water v Methylone 2% 13 75E 1410s 14 1o9' Chloride 9.. '1- e. A

600 (Dover-10,000 )over10,'000 loverlmooll' 10 0.1 240 1,200 1,800 .-1, 800" v 10 01 0.01 to 120 V 120, 10 01 0.1 Z30 .'260' .L A 1.v

Omitingsoitened, butnot loosened. WWI.-. N.

The following table sets forth the relative strip- 15 acids in improving the stripping power of nieth ping power of the methylene chloride-acid-waylene chloride or methylene chloride and water ter compositions of which the acids denominated is further-exemplified when it is considered that are those which I have discovered to'posssess'th "such' acids as oxalic, tartaric, citric,"boric and unusua a t va effect p the Stripping hydrochloric when admixed in the same proporability of yle e C o e 0 tions with methylene chloride and water as in ride containing a small amoun of W r: the above table, all failed to produce a stripping 'i actionqual' tdthetime required fof'methylene chloride and water alone. Hence, it will be seen l I .that certainacids, bothorganic and inorganic, ."i; 3 3%? tend to upp e ememb ot ve eo enhance (timein the stripping ability-of themethylene chloride seconds c m 10 t M th 1 on! lid 1 th retlluiredto solvent gr a l l ing ge ts gf c id aid v t c rrpar ts bg lilme? c iflii g be seen"from annexed" drawlng, unless otherwise noted) completely stripping; power activating eifect of theacid ingredients istope found-in the range of 0. 1 to hy weight of acid on the basis of the total. com- 14105 m position, Y Likewise, the preferred range of water 7 content is 0.01 to 6% by weight on the basis of the mm Add w t o m 5 3 total composition. e l ow e a ples set Acetic Acid 0.1, Water 0.1-- V 20' 110 forth some preferred formulationsembodying my Propionic Acid 0.1, Water 0.1

Salicylic Acid 0.! (by wt), Water 0.1- Butyric Acid 0.1, Water 0.1 Carbolic Acid 0.1 (by'wtl); Water 0.1

"30 260 invention and serving as a further illustration, 40 but not limitation, thereof. The following forj 100 v,260 rnuiations, having methyl cellulose and methanol Nitric Acid 0.l, Water 0. 3911101 Md (by Water presentpossess thixotropic properties, the advan- 350 Cinnamic Acid 0.1 (by wt), Water 0.1 160 420 40 tages of whichrare more fullydescribed in my co pending 1L3. patent application Serial No. 626,172 The unexpected nature of'the above selected filedNovemher 1,; 1 99% A 7 Example 1 [Information No. 1070] Per cent Per cent stripping Constituent Amount y Water Weight Omen E 72 E 14105 14109 Methylene Chloride 00..... 78.78 30 30 30 75 Parafiim. 1 g. 0, 59 Methyl Cellulose (4000 cps) 2 g. 1. 18 Water 2 cc. 1. l8 1. 18 Wetsit Concentrated" 10 cc 5.90 l. 18 Methanol 6, 54 Proplonic Acid 5. 83

Example 2 [Formulation No. 1205] Per cent Per cent stripping Power Constituent Amount y ater might 70E 72 75E 14105 14100 Methylene Chloride lOO co".-- 10 20 10 80 70 "Patent Blue" dye is also known as Xylenblau; for its chemical constituency, refer to FarbenChem1e Fierz-David and Blangey (J. W. Edwards, 1944), p. 286.

Emmi

The stripping abilities of these two above formulations are noted under the sub-heading Stripping Power, for the U. S. Navy Aeronautical Specification test panels 70E, 72 and '75E-arid U. S. Army Air Force Specification test panels 14105 and 14109.

In the following exemplary formulation, carbolic acid or phenol is employed as the acid ingredient, and a chemically basic compound, such as caustic soda, water glass, morpholine and the like, added, which has the effect of improvingthe non-corrosiveness of the composition on metals. The stripping power of the following formulation.

is equivalent to that of the formulations previousw :1 sentiany of thylene chloride present in maijot proportion; 0.1"t0 %by' weight, anhydrous ba4 sis,.of acetic acid, and .0.01 to 6.0% --0L waterrby weight on the basis of the total composition;-

4. A paint remover composition consisting-es sentially':otm'ethylene chloride present in major proportion, 0.15 to 50%by weight, anhydrouslbasispof carbolic acid,iand 0.01 to 6.0 of water by weight on. the basisiotthe total composition.

1y given. LESTER E. KUENTZEL.

. E'a'iample' 3 l' [Formulation No. 2316} Peioem Per cent Strippmg Power: Constituent Amount I By Water-* weght 1 E 72 75B 14105 14109 Methylene Chloride r 100 00.; r96- 15 10 10 30" 40 Parafiin Wm 4 g 2. 43 I Methyl Cellulose (1500 cps.) 1 0. 61 \Yetsit-Goncentrated 3. 03 0.606- Water Glass 0.85 Phenol (Solid) 12. 12

Equivalent modesof practicing my invention may be followed *pr'ovidedtha-t they 'arewitl'iiii the scope and purview of'the" appended' claimsi I,"'therefore, distinctly clainr and parti'cula'rly REFERENCES CITED The"foll0wing references are of record in the file 'of this patent:

point out as my invention: UNITED STATES PATENTS 1. A paint'remover compcsitionconsi'sti'ng es Number Name Dat sent'ially of methylene chloride" and 011 to -50 %-"by 1,095,270 Ellis May 5', 1914 weight, anhydrous basis; of ana'cid selected "from 1,147,849 Ellis .July: 27,1915" the group consisting of formicg'a'ceti'c; propioni'c, 1,147,850 Ellis July 27,1915 salicylic, butyric, carb'olic, benzoic and binnami 1, 18,22 Wilson July 11,1933 acids; and water in the amount of 0.01' .lt0=6.0%' 2,327,701 Ellis Aug.j24,i.1943 byweight on the basis of the" total compo'si'tion: 2,418, 33 Packer Apr. 1, 1947 2. A- paint remover"composition consistiiig "9S: FOREIGN PATENTS sentially of methylene chloride present in majoi 45 Number Country Date 485,857 Great Britain May 20, 1938 

1. A PAINT REMOVER COMPOSITION CONSISTING ESSENTIALLY OF METHYLENE CHLORIDE AND 0.1 TO 50% BY WEIGHT ANHYDROUS BASIS, OF AN ACID SELECTED FROM THE GROUP CONSISTING OF FORMIC, ACETIC, PROPIONIC, SALICYLIC, BUTYRIC, CARBOLIC, BENZOIC AND EINNAMIC ACIDS; AND WATER IN THE AMOUNT OF 0.01 TO 6.0% BY WEIGHT ON THE BASIS OF THE TOTAL COMPOSITION. 